Some people keep telling me that I must unplug my cellphone charger when it's not in use, as it uses electricity even when its not plugged into a
phone.
I don't see how that can be, when their is no load on the charger. Where is this supposed electricity going?
Anyone care to agree/disagree/explain?
Cheers
Fred W B
I'd guess throught the input coil on the transformer. even when there is no output load.
does it get warm. Then its using up electricity.
Paul
Well made coils are very efficient, 99.99% or better.
No phone plugged in then it will draw very little power, as you load the output it pushes back on the primary windings which then draw more
current.
The only place the power will go when the phone is not plugged in is heat, if its not getting hot then only a tiny bit of current is being drawn.
Regards Mark
True, but isn't it just easier to unplug it?
Our cell phone chargers don't seem to get that warm, so I'm happy to leave them be. It's probably 10p a year or something. However, I
have a charger for a rechargeable light that almost glows even when there's nothing plugged into it, that gets unplugged as soon as the light is
charged.
As Mark says, it must be the quality of the charger. My phone would require a pretty decent 5 volt feed with the ability to cut off, so the
electronics must be a bit clever. Whereas the rechargeable light is effectively a nicad battery with no need for proper voltage management, so I
wouldn't be surprised if it's little more than a diode bridge and a big capacitor after the transformer!
Interestingly, my phone actually tells me to unplug my charger once it's finished charging. So even Nokia believe it to be true.
Modern wall chargers for electronics used switched mode power supply solid state circuits. They don't have the "iron" aka transformer in them anymore. If well designed it should have very low power dissipation even when in use so low power losses.
I remember a few years ago, a TV programme that showed how inefficient 'normal' filament bulbs were by having two 60watt lamps in a box with
a (prepped for cooking!) chicken. The chicken was properly cooked in two hours. Obviously folks were amazed how much energy these lamps wasted. To me,
I was thinking what a brilliant secondary benefit. These lamps help heat up the room when you're using it. I wonder how much more output your
central heating has to provide to make up for these daft 'energy' lamps that seem to take forever to give a decent light?
So instead of switching off any chargers, just sit a bit closer to them and reap the benefits.
I'm thinking of swapping my gas combi boiler because the silly little window where the burner lives doesn't give off enough light to read
by......
quote:
Originally posted by owelly...To me, I was thinking what a brilliant secondary benefit. These lamps help heat up the room when you're using it....
a very bright chap at cambridge uni got sick of all the crap science about green energy. He wrote a book. He caused quite a stir and got invited into
the government energy working party.
If i remember correctly its something like leave a charger plugged in and it will consume 1w. Its basically such a small return its not worth worrying
about. The reason people pick on it is that its a very obvious easy change to get people thinking about being energy efficient - the first easy
step.
link to his web site
http://www.withouthotair.com/about.html
The only problem with leaving mobile chargers and like plugged in is the fire risk --- very very low risk but you can quite easily have a dozen+ chargers or other power supplies plugged in in a normal house.